The present invention relates generally to synthesizing signals that have more than one meaning and using these signals to effect different actions. These signals can be useful for wirelessly controlling multiple devices.
Wireless control of multiple devices via a singular signal has many applications. One example of a useful application is in vehicle theft and recovery. Vehicle theft continues to be an ongoing problem. Accordingly, various anti-theft devices have been proposed and are currently in use. Some anti-theft devices are operable to disable one or more vehicle operating systems, thereby disabling the vehicle. Other anti-theft devices use a tracking system to locate and retrieve stolen vehicles. Such vehicle recovery apparatus generally includes a central transmitter, a locator module attached to the vehicle to be recovered, and one or more locating towers. The central transmitter is adapted to send a call signal in response to a report of a stolen vehicle. A receiver in the locator module attached to the vehicle responds to the call signal and activates a location transmitter. The location transmitter generates a tracking signal which is received by the locating towers. The locating towers use the tracking signal to develop vehicle location information As a result, the vehicle recovery apparatus is able to locate a vehicle based on certain parameters of the received locator signal, such as signal strength.
The effectiveness of recovery systems is predicated upon installing the locator module in a concealed location in the vehicle. Otherwise, the locator module may be removed from the vehicle, rendering the recovery apparatus useless. It is also desirable for any disabling apparatus to be similarly concealed.
While these previous vehicle recovery systems have proven reliable, unfortunately they are not infallible. Stolen vehicles having conventional recovery apparatus may be driven into areas in which transmission of the tracking signal is blocked or distorted. For example, the tracking signal typically does not transmit clearly through metal structures. As a result, the previous vehicle recovery systems are not entirely effective.
It has been proposed to provide disabling apparatus with existing recovery apparatus to thereby disable the vehicle until it may be located and recovered. One approach incorporates a VHF band radio receiver (including full demodulation) in the disable module which would activate the disable module in response to either the call signal or the tracking signal. Such systems which require a VHF band radio receiver, however, are overly expensive and require overly complex demodulation. In the alternative, it has been proposed to modify the locator module so that it separately communicates activated status using a radio frequency transmitter and receiver scheme similar to remote keyless entry systems. While this approach would allow the disable module to use less expensive receivers, a separate low power transmitter must be installed in the locator module. Yet another proposed approach would connect a data wire between the locator module and the disable module. This approach, however, may allow a thief to find and remove the locator module and disable module simply by following the connection from the vehicle operating system to the disable module and then following the data wire to the locator module.
Thus, there is a need for disable module which may be used in conjunction with a locator module on a vehicle and which is inexpensive, requires minimal modifications to the locator module, and may be completely concealed in the vehicle.